The present invention disclosed herein relates to an optical device, and more particularly, to an optical device using a silicon semiconductor technology.
Recently, many researches are being made on an optical device using a silicon semiconductor technology. The optical device is applied to a silicon-based electronic device, thereby exceeding the speed limit of the interconnection of the electronic device. It is required that the optical device extracts a portion of the light of an optical waveguide or wavelength-selectively extracts it to transmit the extracted light to other optical waveguide, or extracts only a minimum of an optical power to monitor it, in the inside of a chip.
For this, a directional coupler or a ring-resonator filter is used. The devices have limitations in that they must well define the gap between two optical waveguides in process. A coupling efficiency is greatly changed on the small change of the gap. Moreover, the devices have difficulty in extracting only a certain optical power or a certain wavelength. In a case of the ring-resonator filter, since the line width of a filtered optical spectrum is narrow, it is difficult to extract the light of a wide wavelength region.